Method for transformating color image on image processing system

ABSTRACT

The present invention relates to method for processing colour image on image processing system. The method for processing colour image on image processing system includes the steps of: extracting from the colour image hue, luminance and saturation which are the factors of the colour image; setting the saturation factor as predetermined constant by normalizing the saturation factor; transforming the colour image into complex number using the hue factor and luminance factor. Accordingly, an image processing system can reduce the load of colour image processing by way of present invention that reduces the redundancy between the factors of colour images through transforming the three factors of the colour image into complex number.

TECHNICAL FIELD

[0001] The present invention relates to a method for processing colourimage; and more particularly, to a colour image processing method on animage processing system that transforms factors of the colour image tocomplex number for image processing, and a computer-readable recordingmedium for recording a program that embodies the method.

BACKGROUND ART

[0002] Generally, a colour image is represented by the three (3) primarycolours of light (Red, Green and Blue). But if you represent an image bythe three (3) primary colours of light, you have the large amount ofdata on the image because each of the three (3) primary colours hasstrong correlation to the other and has redundant data.

[0003] So, there are a lot of conventional methods for representingcolour images and one of the conventional methods is that representingcolour images by luminance, hue and saturation that can reduce redundantdata between the colour image factors. These values representing thecolour image are being used in compressing, extracting thecharacteristic value of colour images, etc.

[0004] But, even though the conventional method is an efficient way ofreducing the redundant data between the three (3) factors of colourimage, it complicates mathematical computation and image process incompressing and extracting the characteristic value of colour imagebecause it still uses the three (3) factors of colour image.

DISCLOSURE OF INVENTION

[0005] It is, therefore, an object of the present invention to provide amethod for processing colour image, and a computer-readable recordingmedium for recording a program that embodies the method. The methodtransforms the colour image into hue, luminance and saturation that arethe factors of the colour image. Because the saturation factor affectshuman visual sensation least, the method sets the saturation factor aspredetermined constant, which reduces the factors of the colour imagefrom three (3) to two (2). After that, the method transforms the colourimage into complex number using the hue factor and luminance factor.

[0006] Accordingly, the present invention provides a method on an imageprocessing system and a computer-readable recording medium for recordinga program that embodies the method as though processing a colour imagewith only one (1) factor of the colour image.

[0007] Those who are skilled in the art of the present invention willeasily recognize another purposes and advantages of this invention fromthe drawings, detailed description of the invention, and claims.

[0008] In accordance with one aspect of the present invention, there isprovided a method for processing colour image on image processing systemincludes the steps of: a) extracting from the colour image hue,luminance and saturation which are the factors of the colour image; b)setting the saturation factor as predetermined constant by normalizingthe saturation factor; and c) transforming the colour image into complexnumber using the hue factor and luminance factor.

[0009] In accordance with one aspect of the present invention, there isprovided a computer-readable recording medium for recording a programfor performing a method for processing colour image in an imageprocessing system provided with a processor, the method comprising thesteps of: a) extracting from the colour image hue, luminance andsaturation which are the factors of the colour image; b) setting thesaturation factor as predetermined constant by normalizing thesaturation factor; and c) transforming the colour image into complexnumber using the hue factor and luminance factor.

[0010] The above and other objects and features of the present inventionwill become apparent from the following description of the preferredembodiments given in conjunction with the accompanying drawings. First,in giving reference number to the elements of the drawings, we tried togive the identical elements the same number as much as possible,although they are shown in different drawings. Also, when it isdetermined that too much detailed description on the related prior artmay make the points of this invention blurry, that description isomitted. Referring to accompanying drawings, the preferred embodimentsof the present invention will be described in detail, hereinafter.

BRIEF DESCRIPTION OF DRAWINGS

[0011] The above and other objects and features of the present inventionwill become apparent from the following description of the preferredembodiments given in conjunction with the accompanying drawings, inwhich:

[0012]FIG. 1 is block diagram for describing an image processing systemaccording to an embodiment of the present invention;

[0013]FIG. 2 is exemplary views of complex valued colour model accordingto the present invention; and

[0014]FIG. 3 shows flow diagram illustrating the method of processingcolour image on an image processing system in accordance with anembodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0015] Other objects and aspects of the invention will become apparentfrom the following description of the embodiments with reference to theaccompanying drawings, which is set forth hereinafter.

[0016]FIG. 1 is block diagram for describing an image processing systemaccording to an embodiment of the present invention.

[0017] As shown in FIG. 1, a colour image processing system according tothe present invention includes colour-extracting means 12 for extractingthree (3) factors of hue, saturation and luminance from the colour image10, and complex value processing means 14 for fixing the saturationfactor as predetermined constant and for transforming the colour image10 to complex number by the hue factor and luminance factor.

[0018]FIG. 2 is exemplary views of complex valued colour model accordingto the present invention.

[0019] As shown in FIG. 2, RGB (Red, Green, Blue) Colour Model and HLS(Hue, Luminance, Saturation) Colour Model are of three (3)-dimension.Complex Valued Colour Model are of two (2)-dimension of which X axis isimaginary part and Y axis is real part of complex number, the complexnumber representing the hue factor and luminance factor of the colourimage.

[0020] Complex Valued Colour Model (a) of FIG. 2 is one having the huefactor (H) as phase part and luminance factor (L) as absolute value partof the complex value.

[0021] Complex Valued Colour Model (b) of FIG. 2 is one having the huefactor (H) as imaginary part and luminance factor (L) as real part ofthe complex value.

[0022]FIG. 3 shows flow diagram illustrating the method of processingcolour image on an image processing system in accordance with anembodiment of the present invention.

[0023] As shown in FIG. 3, the method in accordance with the presentinvention transforms the colour image 10 into hue, luminance andsaturation factors 100. After the method then sets the saturation factoras predetermined constant 102, the method transforms the colour image 10into complex number using the hue factor and luminance factor 104, whichresults in construction of complex valued colour image.

[0024] There are various colour models including HSI (Hue, Saturation,Intensity), HSV (Hue, Saturation, Value), HLS (Hue, Luminance,Saturation), etc. that can be used in the step of transforming thecolour image 10 into hue, luminance and saturation factors 100, and thisstep of transforming the colour image 10 using HLS (Hue, Luminance,Saturation) colour model is disclosed in this specification.

[0025] The HLS model transforms inputted image through the equations 1below:

[0026] (Equations 1)

[0027] Luminance (L):${L = \frac{{\max \left( {r,g,b} \right)} + {\min \left( {r,g,b} \right)}}{2}};$Saturation  (S): $\begin{matrix}{{S = \quad \frac{{\max \left( {r,g,b} \right)} - {\min \left( {r,g,b} \right)}}{{\max \left( {r,g,b} \right)} + {\min \left( {r,g,b} \right)}}},} & {\quad {{{for}\quad 0} < L \leq 0.5}} \\{{S = \quad \frac{{\max \left( {r,g,b} \right)} - {\min \left( {r,g,b} \right)}}{2.0 - {\max \left( {r,g,b} \right)} - {\min \left( {r,g,b} \right)}}},} & {\quad {{{{for}\quad 0.5} \leq L < 1.0};{and}}}\end{matrix}$ Hue  (H): $\begin{matrix}{{H = \quad \frac{60\left( {g - b} \right)}{{\max \left( {r,g,b} \right)} - {\min \left( {r,g,b} \right)}}},} & {\quad {{{for}\quad r} = {\max \left( {r,g,b} \right)}}} \\{{H = \quad {120 + \frac{60\left( {b - r} \right)}{{\max \left( {r,g,b} \right)} - {\min \left( {r,g,b} \right)}}}},} & {\quad {{{for}\quad g} = {\max \left( {r,g,b} \right)}}} \\{{H = \quad {240 + \frac{60\left( {r - g} \right)}{{\max \left( {r,g,b} \right)} - {\min \left( {r,g,b} \right)}}}},} & {\quad {{{for}\quad b} = {\max \left( {r,g,b} \right)}}}\end{matrix}$

[0028] (‘r’, ‘g’ and ‘b’ represent the colour of red, green and blue ofthe colour image respectively)

[0029] After transforming the colour image 10 into hue, luminance andsaturation factors using the colour model 100, the step of normalisingthe saturation factor as predetermined constant between 0 and 1 isperformed.

[0030] The saturation factor is utilised not in transforming originalcolour image to complex valued colour image, but in transforming complexvalued colour image to original colour image.

[0031] It is desirable that the saturation factor should be set as themiddle value in the normalised range (O to 1).

[0032] Setting the saturation factor as the middle value in thenormalised range can reduce query computation of the saturation factorin the process of transforming complex valued colour image to originalcolour image.

[0033] As the complex value processing means 14 transforms the inputtedimage to the complex valued colour image by the hue factor and luminancefactor, the complex value is constructed with the luminance factor ofthe inputted image assigned to the absolute value part and the huefactor of the inputted image assigned to the phase part of the complexvalue respectively.

[0034] Transforming equation 1 (Equation 2) or Transforming equation2(Equation 3) is utilised to transform the inputted colour image,already transformed to hue, saturation and luminance factor, intocomplex number:

[0035] (Equation 2)

C1=L×e ^(jH)=[cos(H)+j sin(H)]

[0036] (‘L’ represents the luminance factor and ‘H’ represents the huefactor of the colour image)

[0037] (Equation 3)

Cl=L+jH

[0038] (‘L’ represents the luminance factor and ‘H’ represents the huefactor of the colour image)

[0039] The transforming equation 1 has the luminance factor of thecolour image as the absolute value part and the hue factor of the colourimage as phase part of the complex value.

[0040] The transforming equation 2 has the luminance factor of thecolour image as real part and the hue factor of the colour image asimaginary part of the complex value.

[0041] From now on, a method for searching the colour image as one offields where the complex valued colour image by the process describedabove can be utilised is disclosed.

[0042] First, the colour-extracting means 12 transforms inputted imageto hue, luminance and saturation factors using the Equations 1, andnormalise the saturation factor as the predetermined constant between 0and 1.

[0043] The complex value processing means 14 then constructs complexvalued colour image by transforming the inputted colour image to acomplex number using the Equation 2 or Equation 3 with the hue factorand luminance factor.

[0044] After the construction of complex valued colour image, means forextracting characteristic value extracts the characteristic value fromthe complex valued colour image and database is set up with thecharacteristic value.

[0045] With the database, the inputted image similar to query image canbe searched and outputted by constructing complex valued colour image ofquery image identical to the step of constructing complex valued colourimage of inputted image, extracting the characteristic value from thecomplex valued colour image of query image in the means for extractingcharacteristic value, and comparing characteristic value of query imagewith characteristic value of inputted image stored in the database.

[0046] It is apparent that the colour image processing method accordingto the present invention can be used in various fields besides the fieldfor searching the colour image.

[0047] Accordingly, an image processing system can reduce the amount ofcolour image process or computation by way of present invention thatreduces the redundancy between the factors of colour images throughtransforming the three factors of the colour image into a complexnumber.

[0048] While the present invention has been described with respect tocertain preferred embodiments, it will be apparent to those skilled inthe art that various changes and modifications may be made withoutdeparting from the scope of the invention as defined in the followingclaims.

What is claimed is:
 1. A method for processing colour image on imageprocessing system includes the steps of: a) extracting from the colourimage hue, luminance and saturation which are the factors of the colourimage; b) setting the saturation factor as predetermined constant bynormalizing the saturation factor; and c) transforming the colour imageinto complex number using the hue factor and luminance factor.
 2. Themethod of claim 1, wherein the step a) extracts the factors of thecolour image from the colour image using the equations below:(Equations) Luminance (L):${L = \frac{{\max \left( {r,g,b} \right)} + {\min \left( {r,g,b} \right)}}{2}};$Saturation  (S): $\begin{matrix}{{S = \quad \frac{{\max \left( {r,g,b} \right)} - {\min \left( {r,g,b} \right)}}{{\max \left( {r,g,b} \right)} + {\min \left( {r,g,b} \right)}}},} & {\quad {{{for}\quad 0} < L \leq 0.5}} \\{{S = \quad \frac{{\max \left( {r,g,b} \right)} - {\min \left( {r,g,b} \right)}}{2.0 - {\max \left( {r,g,b} \right)} - {\min \left( {r,g,b} \right)}}},} & {\quad {{{{for}\quad 0.5} \leq L < 1.0};{and}}}\end{matrix}$ Hue  (H): $\begin{matrix}{{H = \quad \frac{60\left( {g - b} \right)}{{\max \left( {r,g,b} \right)} - {\min \left( {r,g,b} \right)}}},} & {\quad {{{for}\quad r} = {\max \left( {r,g,b} \right)}}} \\{{H = \quad {120 + \frac{60\left( {b - r} \right)}{{\max \left( {r,g,b} \right)} - {\min \left( {r,g,b} \right)}}}},} & {\quad {{{for}\quad g} = {\max \left( {r,g,b} \right)}}} \\{{H = \quad {240 + \frac{60\left( {r - g} \right)}{{\max \left( {r,g,b} \right)} - {\min \left( {r,g,b} \right)}}}},} & {\quad {{{for}\quad b} = {\max \left( {r,g,b} \right)}}}\end{matrix}$

WHEREIN the r, g and b represent the colour of red, green and blue ofthe colour image respectively.
 3. The method of claim 1, wherein thestep b) normalises the saturation factor as the predetermined constantbetween 0 and
 1. 4. The method of any one of claim 1 to 3, wherein thesaturation factor is utilised not in transforming original colour imageto complex valued colour image, but in transforming complex valuedcolour image to original colour image.
 5. The method of any one of claim1 to 3, wherein the saturation factor is set as the middle value in thenormalised range.
 6. The method of any one of claim 1 to 3, wherein thestep b) transforms the colour image to complex valued colour image usingthe transforming equation 1 below: (Transforming equation 1) Cl=L×e^(jH)=[cos(H)+j sin(H)] WHEREIN the L represents the luminance factorand the H represents the hue factor of the colour image.
 7. The methodof any one of claim 1 to 3, wherein the step b) transforms the colourimage to complex valued colour image using the transforming equation 2below: (Transforming equation 2) Cl=L+jH WHEREIN the L represents theluminance factor and the H represents the hue factor of the colourimage.
 8. The method of claim 6, wherein the transforming equation 1 hasthe luminance factor of the colour image as the absolute value part ofthe complex value.
 9. The method of claim 6, wherein the transformingequation 1 has the hue factor of the colour image as phase part of thecomplex value.
 10. The method of claim 7, wherein the transformingequation 2 has the luminance factor of the colour image as real part ofthe complex value.
 11. The method of claim 7, wherein the transformingequation 2 has the hue factor of the colour image as imaginary part ofthe complex value.
 12. A computer-readable recording medium forrecording a program for performing a method for processing colour imagein an image processing system provided with a processor, the methodcomprising the steps of: a) extracting from the colour image hue,luminance and saturation which are the factors of the colour image; b)setting the saturation factor as predetermined constant by normalizingthe saturation factor; and c) transforming the colour image into complexnumber using the hue factor and luminance factor.